Flame-retardant and intumescent compositions

ABSTRACT

NOVEL ADJUVANTS AND COMBINATIONS THEREOF ARE PROVIDED WHICH HAVE THE POPERTIES OF IMPORTING FLAME-RETRADANCY AND INTUMESCENCE TO POLYMERIC MATERIALS. THE NEW ADJUVANTS COMPRISE HALOGENATED AND PHOSPHORUSCONTAINING ADJUVANTS OF DIALLYL CHLORENDATE AND MINERAL ACID SALTS OF PHENYLBIGUANIDINE DERIVATIVES. THE LATTER MAY BE ADVANTAGEOUSLY COMBINED WITH A WIDE VARIETY OF PHOSPHORUS-CONTAINING COMPOUNDS, INCLUDING ESPECIALLY, NOVEL DIALLYL CHLORENDATE DERIVATIVES TO PROVIDE INTUMESCENT FILMS AND COATINGS.

3,728,138 ented Apr. 17, 1973 3,728,138 FLAME-RETARDAN T AND INTUMESCENT COMPOSITIONS Int. Cl. C09d /18 US. Cl. 106-45 FP 10 Claims ABSTRACT OF THE DISCLOSURE Novel adjuvants and combinations thereof are provided which have the properties of importing flame-retardancy and intumescence to polymeric materials. The new adjuvants comprise halogenated and phosphoruscontaining adjuvants of diallyl chlorendate and mineral acid salts of phenylbiguanidine derivatives. The latter may be advantageously combined with a wide variety of phosphoruscontaining compounds, including especially, novel diallyl chlorendate derivatives to provide intumescent films and coatings.

- This is a division of application Ser. No. 726,538, filed May 3, 1968, now US. Pat. No. 3,639,535, granted Feb. 1, 1972.

This invention relates to compositions having flameretardant characteristics, to compositions having intumescent characteristics, to components which impart such characteristics to such compositions and to methods of preparation of such components and compositions.

The need for flame-retardant construction and decorating materials in the building arts and trades has gained substantial importance in recent years and, accordingly, the search for components suitable for imparting flameretardant characteristics to such materials as paints, coatings, films, foams and the like, has been unremitting and wide-spread. With respect to films and coatings, a very desirable characteristic, in addition to simple flame-retardancy, that is, in addition to the self-extinguishing and non-burning properties of the material, is that of intumescence whereby the coating or film swells or bubbles up when subjected to heat or flame to provide a coherent shield spaced apart from the substrate which protects the same from attack by fire. Optimally, therefore, components introduced into films and coatings for the purpose of rendering them fire-resistant will include not only components which impart flame-retardancy thereto, as that term is ordinarily understood, but also components which impart the characteristic of intumescence as well.

It is accordingly, an object of this invention to provide novel compositions which impart the characteristics of flame-retardancy to polymeric materials when incorpo= rated thereinto.

It is another object of this invention to provide com= positions which impart characteristics of flame-retardancy and intumescence to polymeric materials, especially films and coatings, when incorporated thereinto.

It is another object of this invention to provide polymeric compositions having the characteristic of flame-re-= tardancy. 1

It is another object of this invention to provide polymeric compositions having the characteristic of intumescence.

It is another object of this invention to provide method. for preparing polymeric materials having 'c haracteristics cf fiame-retardancy., f;and both fiame retardancy-"- nd'" tumescence'. I in accordance withthis invention,

and still further objects are broadly achieved by provid-= ing classes of compounds suitable for incorporation into polymeric materials to impart fiame-retardancy and, in some cases, intumescence thereto. A novel fiame-retard- 'ant composition as provided in accordance with this invention is characterized by the following generalized formula wherein X is selected from the group consisting of halogen atoms having an atomic weight greater than 30 and the group -PO(OR) in which R is selected from the group consisting of alkyl radicals containing from 1 to 4 carbon atoms, alkenyl radicals containing from 1 to 4 carbon atoms, alkenyl radicals containing from 1 to 4 carbon atoms substituted with at least 2 halogen atoms having an atomic weight greater than 30, a phenyl group substituted with a halogen atom having an atomic weight greater than 30.

Products defined by the formula given above may be prepared by the halogenation in the presence of butyl al-= cohol and at temperatures below C., perferably be tween about 0 C. and 30 C. of di-allyl chlorendate, an ester which is itself an easily available commercial product and which may also be easily prepared by reacting one mole of chlorendic anhydride with two moles of allyl alcohol. Chlorendic acid or its anhydride may be prepared by conventional chemical processes by reacting hex achlorocyclopentadiene with maleic acid or maleic anhydride respectively. A preferred halogen for use in the preparation of compounds useful to impart fireretardancy to films, coatings, foams and similar polymeric materials in accordance with this invention is bromine. The following. chemical equation illustrates the preparation of a typical bromine-containing component suitable for use in the preparation of fire-retardant poly= meric materials in accordance with the present invention:

-o OgCHzCHBrCHeBl Cl- -01 COzCHzCHBrCH Br The phosphorus'containing compounds defined by the generalized formula set forth above may be produced by reacting at an initial temperature of from about 50 C. to 60 C. the halogenated product with an alkali metal salt of a phosphorus acid ester such as dialkyl phosphite, trialkyl phosphite or a diaryl phosphite while refluxing in suitable solvent within a temperature range of about 70 C. to about 200 C. Alkyl groups forming the phos phoric acid ester may be methyl, ethyhpropyl or'butyl -r adical's. --The aryl group may be the phenyl radical or a haloph enyl radical. The following generalized chemical equation is illustrative of the preparation of phosphorus containing compositions conforming to the formula set forth above:

H PO(OCHn): -onicmo11crn1 0(0 can now -01 oozonzononrrowclam in. Pomona? H PO(O CzHi):

x\ --C OzCHzHCHz-P (O C1115): Cl

/ "CORCHICHCHPP 0 (O C2115):

The following is a specific example of the preparation of a halogenated diallyl chlorendate suitable for use in accordance with the present invention:

EXAMPLE 1 The reaction is carried out in a suitable 3-necked flask equipped with stirrer, reflux condenser and dropping funnel. 467 grams (1 mole) of diallyl-chlorendate are dissolved in 200 ml. of butanoli The reaction flask is then placed into an ice-water bath and from a dropping funnel 320 grams (2 moles) of bromine are added dropwise to saturate completely the diallyl' chlorendate. The bromine may be added until the solution is no longer decolor ized by addition of more bromine -at this point 2 moles of bromine per mole of diallyl chlorendate have been added and the resulting reaction product is a brorninated diallyl chlorendate having a chemical structure which accords with Formula 21 above,

The following is a specific example of the preparation of a phosphorus-containing roduct suitable for use to impart flame-retardant characteristics to polymeric materials in accordance with the present invention:

EXAMPLE 2;

In a suitable vessel, 92 grams (4 moles) of sodium are dissolved in 200 grams of butanol and 776 grams (4 moles) of dibutyl phosphite. When all sodium is dissolved or has been converted to sodium dibutyl plrqsphite, the resulting solution is then ad e to ih e product obtained in Example 1 at about C.- Q The addition of sodium dibutyl phosphite to the brorninated diallyl chlorendate results in a reaction which is exothermic in character. When all sodium dibutyl phosphite has been added, the mixture is refluxed. at a temperature between C. C. for three hours to ensure complete condensation. The condensation is complete when no more sodium bromide is formed. After cooling the solution is washed salt free and the butanol is removed under vacuum. The resulting product has low viscosity, is clear and slightly brownish'. The product conforms in its chemical structure to Formula o above, The yield is about 98%.

Another class of flame-retarding compositions useful in the practice of the present invention is exemplified by mineral acid salts of compounds broadly characterized by the following generalized formula;

(2) NE NH HzN lL-NH ()--NII wherein X is a halogen having an atomic weight greater than 30 and n is a number from 0 to 5.

Compounds comprised by the preceding formula may be prepared, in general, by reacting a suitable acid salt of aniline and dicyandiamide in molar proportions in. an acid medium. As a practical matter, any mineral acid may be used; however, hydrochloric acid is preferred.

NH NH The following are representative compounds useful in preparation of flame-retardant materials in accordance with this invention:

Br NH NH 1 I The following specific example illustrates the preparation of a typical composition suitable for use to impart fiame-retardancy to plastic and polymeric materials conforming to Formula 2 above:

EXAMPLE 3 The reaction is carried out in a 1000 ml., 3-necked' flask equipped with reflux condenser and stirrer. 129.6 grams of aniline hydrochloride (1 mole) is dissolved in 300 ml. of water. Thereafter, 84 grams (1 mole) of dicyandiamide (cyanoguanidine) are added to the solu tion. After addition of a small amount of HCl, the mixture is heated to reflux temperature. During the heating, the dicyandiamide also goes into solution. After about 30 minutes of refluxing, a greenish-gray solid precipitates. The precipitate, which is phenyl-biguanidinehydrochloride, is filtered off and washed with water. After drying, the phenylbiguanidinehydrochloride may be ground into a time powder to be used as a flame-retardant pigment component. The product conforms in its chemical structure to Formula g above.

-in accordance with the present invention, fire-retardant coatings, films, foams and such polymeric materials may be prepared by incorporation thereinto from about 5% to about 60% weight of the total polymeric composition of the chlorendic acid ester derivative hereinbefore described and characterized by Formula 1 above or from about 25% to about 60% by weight of the total polymeric:

composition of the phenylbiguanidine derivative hereinoefore described and characterized by Formula 2 above. In general, the flame-retarding components described herein are compatible with a wide variety of ploymeric materials and resins from which films or coatings and, in some cases, even foams may be made. Among those resinous or polymeric materials with which said flameretardant components are compatible are, for example, polyester resins, polyurethane resins, cellulose derivatives, polymeric vinyl resins, epoxy resins and others.

Polyester resins which are useful in accordance with this invention include linear polyesters made by reacting glycols or other diols with dibasic organic acids and abundantly described in the art. Such linear polyesters comprise the reaction products of dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol,

bisphenol A, prodendro bisphenol A, higher molecular weight polyglycols and numerous other diols and ali phatic dibasic carboxylic acids such as adipic acid, phthalic acid, sebacic acid, fumaric acid and maleic acid and others in proportion to completely esterify the hydroxyl group present in the dihydric alcohol. Crosslinked polyesters made by reacting polyfunctional alcohols, such as glycerol, with the aforementioned aliphatic dibasic carboxylic acids in sufiicient proportion to esterify the hydroxyl groups present in the polyhydric alcohol. Unsaturated polyesters cross-linked with a vinyl-type monomer, such as styrene, may be used. Polyesters which may be used in the practice of the present invention comprise, but are not restricted to, those described and their method of preparation disclosed in US. Pats. 2,453,644; 2,593,787; 2,409,633; 2,443,735; 2,443,741; 2,450,552; 2,255,313; 2,512,410; 2,634,251; 2,662,069 and 2,662,070, all hereby incorporated by reference.

Epoxy resins, characterized by the presence of the p,

are useful in the practice of the present invention and comprise polymeric reaction products of polyfunctional halohydrins, such as epihalohydrins with polyfunctional hydrogen-donating reactants, or their salts, such as polyfunctional phenols, alcohols, amines, acids and their salts. Typical of these is the reaction product of an epihalohydrin, such as epichlorohydrin and bisphenol A. The preparation of such an epoxy resin is described in US. Pat. 2,500,449 in which epichlorohydrin is reacted with bisphenol at C. in the presence of sufiicient to bind the hydrochloric acid formed. The resins formed vary according to the proportions of reactants and reaction conditions. Epoxy resins of the kind useful in the practice of this invention are further described in US. Pats. 2,324,- 483; 2,444,333; 2,503,726; 2,558,949; 2,500,600; 2,467, 171; 2,528,932; 2,582,985 and 2,615,007, all hereby incorporated by reference.

The fire-retardant components of the present inven tion may be used in coatings prepared from synthetic polymer emulsions. Monomers from which such synthetic high polymers may be prepared are in general characterized by the formula wherein R R R and K, may be hydrogen or almost any kind of ligand. -In most cases at least two hydrogen atoms are linked directly to the ethylenic carbon atoms and in the true vinyl monomers R R and R are all hydrogen. Examples of monomers which may be used in surface coating emulsions are vinyl acetate; vinyl chloride; acrylonitrile; vinylidene chloride; styrene; bu= tadiene 1,3; alkyl acrylates, such as ethyl acrylate; alkyl methacrylates, such as methyl methacrylate; alkyl maleates, such as isopropyl maleate; alkyl fumarates, such as isobutyl fumarate; acrylic acid; methacrylic acid; crotonic acid and others. The technique of emulsion polymerization of vinyl esters is well known in the art and is exemplified in U.S. Pat. 2,562,965, hereby incorporated by reference.

The flame-retardant components of the present inven= tion may be used in coatings made of cellulose derivatives and include coatings made from cellulose esters, such as cellulose nitrate, cellulose phosphate, cellulose acetate, cellulose acetate butyrate and others. Coating formed from cellulose ethers may be used. These comprise, for example, methyl cellulose, ethyl cellulose, methyl ethyl cellulose, ethyl hydroxyethyl cellulose and benzyl cellulose.

In accordance with the present invention, the abovedescribed flame-retardant additives may be used in the preparation of a wide variety of polyurethane films, coatings and foams. Coatings and foams comprising multiple urethane linkages formed by the reaction of an isocyanate and a compound containing a hydrogen atom or atoms reactive therewith as, for example, hydroxyl-bearing compounds such as polyesters and polyethers having terminal hydroxyl groups.

Suitable polyesters useful in the preparation of polyurethane coatings and foams in accordance with this invention may be obtained by esterification condensation reaction of an aliphatic dibasic carboxylic acid with a glycol or triol or mixture thereof in such proportion that the resultant polyesters possess predominantly terminal hydroxyl groups. Aliphatic dibasic carboxylic acids which may be used to prepare such polyesters comprise adipic acid, futnaric acid, sebasic acid and phthalic acid, for example, and suitable alcohols include ethylene glycol, dicthylene-glycol, trimethylol propane and others.

Fatty acid glycerides may be used as the hydroxyl-bearing component in the preparation of the polyurethane polymers of the present invention and comprise those having a hydroxyl number of at least 50, such as castor oils, hydrogenated castor oils or blown natural oils.

Polyestcrs, generally, which may be used in the preparation of polyurethane polymers are described in US. Pats. 2,453,644; 2,593,787; 2,409,633; 2,443,735-41; 2,450,552; 2,255,3 l3 and 2,512,410, all hereby incorporated by reference.

Polyethcr hydroxyl-bearing compounds which may be used to prepare both polyurethane coatings and foams in accordance with this invention comprise those having a functionality of two or more, i.e., polyethers which are diols. triols, tetrols, pentols or hexitols. Particularly suitable polyethers are polyoxyalkylene ethers of polyhydric alcohols or amines such as polyoxyalkylene glycols, polyoxyalltylene bisphenol A, polyoxyalkylene sorbitol, polyoxyalkylene methyl glucoside, polyoxyalkylene pentaerithritol, polyoxyalkylene sucrose, polyoxyalkylene trimethylolethane, polyoxyalkylene trimethylol propane, polyoxy alkylene diethylene triamine and polyoxyalkylene glycerine. The polyoxyalkylene ether of the polyhydric alcohol may be prepared, if desired, by reacting an alkylene oxide compound with a selected polyhydric alcohol in the conventional manner. The overall range of alkylene oxide groups per molecule may vary within a range of about 2 to about 80 and the alkylene oxides which may be used comprise ethylene oxide, propylene oxide, butylene oxide and others.

More specifically, among the hydroxy-bearing compounds which may be used to prepare polyurethane polymers useful in the practice of the present invention are polyoxyalkylene bisphenol A containing from 2 to 20 oxyalkylene groups per molecule and including the polyoxyethylene, polyoxypropylene and polyoxybutylene derivatives; 1,2,6-hexanetriol; dipropylene glycol; propylene glycol, ethylene glycol; polyoxyethylene(2)cyclohexane dimerl'ianol: polypropylene glycol (M.W. 1000); glycerine, trimethylol propane; polyoxypropylene(40)sorbitol; polyoxypropylene(20)methyl glucoside; polyoxypropylene {)isosorbide as well as many other polyhydric alcohols indicated, for example, in US. Pat. 2,843,568, hereby incorporated by reference. Accordingly, aromatic, aliphatic and cycloaliphatic hydroxy compounds may be utilized in the preparation of polyurethane polymers. Ethylene oxide, propylene oxide and butylene oxide derivatives of such polyhydric alcohols may be used, as well as hydroxylterminated polyesters derived from saturated or unsaturated dibasic acids, simple glycols and modifying trihydric alcohols. In many cases it will be desirable to use two or more polyhydric alcohols in combination to produce a polyurethane polymer having the desired characteristics.

A wide variety of organic isocyanate compounds may the practice of the present invention, among which are included toluene diisocyanate, diphe 'nyl diisocyanate, tn

phenyl diisocyanate, chloro-phenyl-2,4-diisocyanate, ethyl ene diisocyanate, 1,4 tetramethylene diisocyanate, pphenylene diisocyanate, hexamethylene diisocyanatc, 3,3" dimethyl 4,4'-biphenylene diisocyanate, 3,3dimethoxy- 4,4'-biphenylene dissocyanate, polymethylene polyphenyl polyisocyanate (PAPI), diphenylmethane-2,4'-diisocyamate and others.

Suitable catalysts for the preparation of polyurethane foams comprise amine catalysts and tin catalysts and mixtures thereof. Representative amine catalysts are N alkyl morpholines, such as N-methyl morpholine and N- ethyl morpholine; tertiary amines, such as trimethyl amine, triethyl amine, tetramethylguanidine, triethylene diamine, N,N,N',N' tetramethyl-l,3-butane diamine; piperazine and piperazine derivatives, such as N-methyl piperazine. These amines may be present in amounts from about 0.05% to about 2% by weight of the hydroxyl-bearing compounds reacted with the isocyanate compound. Among the suitable tin catalysts are included dialkyl tin laurates, such as dibutyl tin laurate, dibutyl tin di-Z-ethyl hexoate, dibutyl tin diacetate, stannous oleate and stannous octoate. Tin catalysts may be present in amounts from about 0.1/ to about 1.0% by weight of the hydroxy-bearing compound used in the reaction.

Examples of useful surface active agents which may be used in the preparation of polyurethane foams comprise water-soluble siloxane-oxyalkylene block copolymers as described in US. Pat. 2,834,748, to Bailey et al., condensates of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol having generally the formula 2 4 a( 3 6)b( 2 4 )c Another class of surfactants is comprised by the formula tuot zHt nt aut mz z a i s rht 2 4) 2 Other surfactants comprise the polyoxyalk'ylene esters of long chain fatty acids and sorbitan, such as polyoxyethyl-- ene (20) sorbitan monolaurate, polyoxyethylene(4)sorbi tan monolaurate, polyoxyethylene(20)sorbitan monopalmitate, polyoxyethylenetZO)sorbitan monostearate, polyoxyethylene(20)sorbitan tristearate, polyoxyethylene (5)sorbitan monooleate and others.

A foaming agent, such as a halogenated saturated all phatic hydrocarbon or a mixture of such hydrocarbons, may be used to prepare polyurethane foams suitable for use in the practice of this invention. These comprise, inter alia, trichlrofiuoromethane (Freon ll inonochloro' ethane, monochloromonofiuoroethane, dichloromethane and their mixtures.

In general polyurethane foams are prepared in accord ance with this invention in suitable proportion to provide a ratio of hydroxyl groups to isocyanate groups within a range of about 11 '1.05 to about 1/1.7, with a ratio of about 1/ 1.05 preferred.

The following are specific examples of the preparation of fire-retardant polymeric coatings according to the method of the present invention;

EXAMPLE 4 Moisture-curing flame-retardant polyurethane coating A prepolymer is prepared which is the product of reaction of toluene diisocyanate and polyoxypropylene(10) sorbitol in proportion to provide a ratio of isocyanate groups to hydroxyl groups in the end product of about 4.5 to l. The reaction is carried out in a one-liter, 3- necked round-bottom flask equipped with stirrer, nitrogen inlet, dropping funnel and reflux condenser. 392 grams of toluene diisocyanate are placed in the flask at room temperature under nitrogen and stirring. 114 grams of polyoxypropylene(10)sorbitol are then added over a 30 minute period of time. The reaction is exothermic and the temperature should be held at C. (using a heating mantle) for five hours. After cooling the prepolymer is ready for use. The free isocyanate content is about 28% by weight. The final curing of the urethane coating is achieved by reaction of the free isocyanate groups of the prepolymer with atmospheric moisture.

A clear varnish is prepared by first dissolving 41.7 grams of the urethane prepolymer in 10.4 grams of cellosolve acetate, 5.2 grams of methyl ethyl ketone and 5.2 grams of toluene with slow stirring. The sequence of solvent addition is unimportant. When the prepolymer solution has become clear, 37.5 grams of the phosphoruscontaining allyl chlorendate derivative of Example 2 is stirred into the solution with slow mixing. The varnish is then ready for use.

EXAMPLE 5 Moisturecuring flame-retardant polyurethane coating A. urethane prepolymer is prepared as in Example 4. A varnish is then prepared by dissolving 17.3 grams of the urethane prepolymer in 17.5 grams of cellosolve acetate, 8.75 grams of methyl ethyl ketone and 8.75 grams of toluene with slow stirring. When the prepolymer solution has become clear, 47.7 grams of the phenylbiguanidine hydrochloride of Example 3 are stirred into the solution with slow mixing. The resulting varnish may be used wherever a flame-retardant varnish is required.

The following is a specific example of the preparation of a flame-retardant polyurethane foam in accordance with the method of the present invention:

EXAMPLE 6 Rigid polyurethane foam formulation Percent by weight Component A: polymethylene polyphenyl isocyanate (Mondur MR) 40.0

Component B in the above formulation is prepared by adding together in a suitable vessel each of the named ingredients sequentially in the order and the amounts specified while mixing thoroughly with a high speed mixer. To the homogeneous mixture is then added quickly and in a single addition the entire specified amount of organic isocyanate (Component A), The combined components are then mixed at high speed with a laboratory mixer for about 10 seconds, after which the mixture is poured into a 1 gallon paper cup and allowed to foam. The foam may be determined to have the following properties as indiin accordance with an important modification of this invention fiame-retardant and intumescent films and coatings may be produced by combining therein with a mineral acid salt of a phenylbiguanidine derivative, as .defined by Formula 2 above, a suitable phosphorus-containing flame-retardant component such as those exemplitied hereinafter. In accordance with this invention,

intumescent polymeric materials may be made by incor porating thereinto from about 5% to about 60% by weight of a combination of flame-retardant additives in cluding as necessary ingredients the phenylbiguanidine derivative characterized by Formula 2 above and a phosphorus-containing flame-retardant material. The porpor tions of said necessary flame-retardant ingredients in said polymeric materials may vary from a ratio of about 1 part by weight of said phenylbiguanidine derivative to 1 part by Weight of said phosphorus-containing compound to 20 or more parts by weight of said phenylbiguanidine derivative to about 1 part by weight of said phosphoruscontaining compound, provided, however, that if the phenylbiguanidine derivative should be used in amounts less than about 25% by weight of the composition, then the concentration of said phosphorus-containing compound must be not less than 4% by weight of said polymeric material.

A wide variety of phosphorus-containing compounds may be used in combination with the phenyl biguanidine derivative characterized by Formula 2 above to provide flame-retardant intumescent polymeric materials. Preferred phosphorus-containing flame-retardant additives for use in this connection are those subsumed under Formula 1 above. Many other phosphorus-containing materials may be used, however, including organic esters and partial esters of phosphoric acid, phosphoric acid salts and organic phosphites and phosphonates. Representative of the many phosphorus-containing materials which may be used, for example, are tertiary phosphites, such as trimethyl, triethyl, tripropyl and tributyl phosphite, tri(2-ethylhexyl) phosphite, tridecyl phosphite (iso), trioctadecyl phosphite, triphenyl phosphite, diphenyl pentaerythritol phosphite and phenylneopentyl phosphite; secondary phosphites, such as dimethyl, diethyl, dipropyl and dibutyl phosphite, diallyl phosphite, di(2-ethylhexyl) phosphite, diphenyl phosphite, dioctadecyl phosphite and dilauryl phosphite; phosphonate and phosphorothionate esters, such as dimethyl methyl phosphonate, diallyl allyl phosphonate, dimethyl benzyl phosphonate, trimethyl phosphorothionate and ethylene phenyl phosphorothionate; organophosphorus compounds, such as bis(hydroxymethy1) phosphinic acid, methyl phosphonic acid, trimethallyl phosphite and triallyl phosphate; alkyl acid phosphates having the generalized formula 0 ROJ =(OH)E, (ROhi -OH and (ROMP: wherein R is a radical selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl and cresyl, such as methyl acid phosphate, n-butyl acid phosphate, amyl acid phosphate andlauryl acid phosphate, as well as many other phosphorus-containing flame-retardant additives such as those disclosed in U.S. Pats. 2,691,567; 2,683,168; 3,206,474; 2,795,609; 3,014,944; 3,014,956; 3,042,701 and 3;058,941, all hereby incorporated by reference.

The following is an illustrative example of the prepara tion of a flame-retardant, intumescent coating in accordance with the method of the present invention:

EXAMPLE 7 Flame-retardant nitrocellulose lacquer formulation Ingredient: Percent by weight Nitrocellulose RS /2 sec. (30% butanol) -2- 10.2 Phosphorus-containing derivative of Example 2 14.3 Phenyl biguanidine hydrochloride of Example -2 28.6 Xylene 10.2 Butyl acetate 22.45 Cellosolve acetate 2. 14.25

. .The nitrocellulose, wetted with 30% butanol, is placed in a solution vessel and the diluent (xylene) is added in the quantity specified. Thereafter, the solvents butyl ace tate and Cellosolve acetate are added. The mixture is stirred until the nitrocellulose solution is clear. Finally, flame retardant additives of Examples 2 and 3 are added in the quantities indicated.

It. should be appreciated that the phenylbiguandine derivative acts as a pigment and consequently requires grinding as may any other pigment. Standard equipment used in. paint manufacture may be used for this purpose. It should be further appreciated that the flame-retardant additives may be incorporated into the coating either separately or in the form of a composition prepared in advance for such purpose. The following are representative exmnples of compositions suitable for use in the preparation of intumescent flame-retardant coatings in accordance with this invention:

EXAMPLE 8 Imgredicnt: Parts by weight Compound exemplified by Formula g 1 Compound exemplified by Formula c 1 EXAMPLE 9 Ingredient: Parts by weight Compound exemplified by Formula g Compound exemplified by Formula (1 1 EXAMPLE 10 Ingredient: Parts by weight Compound exemplified by Formula h Compound exemplified by Formula e 1 EXAMPLE 11 ingredient: Parts by weight Compound exemplified by Formula k 10 Compound exemplified by Formula f 1 EXAMPLE l2 Ingredient: Parts by weight Compound exemplified by Formula i 15 Compound exemplified by Formula c 1 EXAMPLE 13 ingredient:

Parts by Weight Compound exemplified by Formula j 18 Tributyl phosphite 1 EXAMPLE l4 Ingredient: Parts by weight Compound exemplified by Formula g 4 Diethyl phosphite 1 EXAMPLE 15 ingredient: Parts by weight Compound exemplified by Formula g 8 Dimethyl methyl phosphonate 1 EXAMPLE 16 ingredient: Parts by weight Compound exemplified by Formula h 12 n'Butyl acid phosphate 1 EXAMPLE 1'7 Ingredient: Parts by weight tiompound exemplified by Formula j 2 Triallyl phosphate 1 The following are further representative examples of the preparation of flame-retardant intumescent coatings according to the method of the present invention:

The nitrocellulose, wetted with 30% butanol, is placed in a solution vessel and the diluent (toluene) is added in the quantity specified. Thereafter, solvents acetone and Cellosolve acetate are added. The mixture is stirred until the nitrocellulose solution is clear and then the wood resin and colloidal silica are added with stirring to achieve a homogeneous solution and mixture. Then are added flameretardant additives of Examples 2 and 3 in the quantities specified.

EXAMPLE 19 Intumescent polyurethane coating A urethane prepolymer is prepared as in Example 4. A varnish is then prepared by dissolving 17.3 grams of the urethane prepolymer in 17.5 grams of Cellosolve ace tate, 8.75 grams of methyl ethyl ketone and 8.75 grams of toluene with slow stirring. When the prepolymer solution has become clear 17.5 grams of the phenylbiguanidine hydrochloride of Example 3 and 4.34 grams of the phosphorus-containing allyl chlorendate derivative of Example 2 are stirred into the solution with slow mixing. The resulting varnish may be used wherever an intumescent flame-retardant coating may be desired.

EXAMPLE 20 Intumescent polyvinyl acetate emulsion based coating formulation Ingredient: Percent by weight Polyvinyl acetate emulsion 48.0 Flame-retardant derivative of Example 2 13.0 Flame-retardant derivative of Example 3 26.0 Water 13.0

A polyvinyl acetate emulsion is prepared from the following materials in the following manner:

Ingredient: Part by weight Water a 43.11 Dodecyl benzene sulfonate a- 0.11 Polyoxyethylene(20)nonyl phenol -c 1.32 Borax 0.25 Potassium persulfate M- M. 0.21 Vinyl acetate e 55.0

EXAMPLE 21 Flame-retardant intumescent polyester formulation.

Ingredient: Parts by weight I Polyester resin (Atlac 382) 40 Styrene 40 Halogenated hydrocarbon (tetrachlorodiphenyl ether) 20 Allyl chlorendate derivative of Example 2 L-.. 5 Methyl ethyl ketone peroxide solution 1 Cobalt naphthenate 1 The polyester resin of the above formulation is an unsaturated polyester resin prepared in the conventional manner by reacting 1 mole of polyoxypropylene(2) bisphenol A with 1 mole of futnaric acid. 40* grams of the polyester resin are dissolved at room temperature in 40 grams of styrene while stirring lightly. When all of the polyester resin has dissolved, 20 grams of halogenated hydrocarbon are added and the mixture stirred until homogeneous. Thereafter, grams of the flame-retardant additive of Example 2 are added together with catalysts. The catalysts are mixed in by hand. After catalyzation, the polyester solution is poured into glass molds and cured at room temperature. The folowing are results of ASTM D-635 flame tests performed on /8 inch castings: A inch in 48 sec.; 3.4 inch in 3 min.

Having thus described my invention, I claim:

ll. A flame-retardant composition containing a resin and from about 5% to about 60% by weight of said composition of a flame-retardant agent selected from the group consisting of phosphorus-containing compounds characterized by the general formula:

wherein X is --PO(OR) in which R is selected from the group consisting of alkyl radicals containing from 1 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms substituted with at least 2 halogen atoms having an atomic Weight greater than 30, a phenyl group and a phenyl group substituted with a halogen atom having an atomic weight greater than 30.

2. A flame-retardant polymeric composition of claim 1 wherein the phosphorus-containing compound is characterized by the formula:

3. A composition of claim 1 wherein the halogen atoms having an atomic weight greater than 30 are selected from the group consisting of bromine and chlorine.

4. A flame-retardant polyvinyl acetate emulsion based coating composition according to claim 1.

57 A flame-retardant nitrocellulose lacquer according to claim 1.

6. A flame-retardant polyester resin composition ac cording to claim 1.

7. A flame-retardant polyurethane composition containing'a resin and from about 5% to about 60% by weight of said composition of a flame-retarding agent selected from the group consisting of a phosphorouscontaining compound characterized by the generalized formula:

wherein K is PO(OR) in which R is selected from the group consisting of alkyl radicals containing from 1 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms substituted with at least 2 halogen atoms having an atomic weight greater than 30, a phenyl group and a phenyl group substituted with a halogen atom having an atomic weight greater than 30 8. A composition of claim 7 wherein the halogen atoms having an atomic weight greater than 30 are selected from the group consisting of bromine and chlorine,

9. A composition of claim 7 which is a polyurethane foam.

10. A composition of claim 7 which is a polyurethane coating composition,

References Cited UNITED STATES PATENTS 3,027,349 3/1962 Bahr et al 260-457 P 3,037,044 5/1962 Bruson et a1. 106-15 FP X 3,257,337 6/1966 Schoepfie et a1, a- 260-2.5 A J 3,396,129 8/1968 Yeadon et al 26077.5 A 3,525,708 8/1970 Clark et al 260--45.85

WILLIAM H. SHORT, Primary Examiner L. M. PHYNES, Assistant Examiner US. Cl. X.R.

260 -25 A], 29.6 MP, 45.7 P, 47 P, T, P, 775 A, 78.5 T

g;g3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION- Patent No. 3 728 138 D t d April 17 1973 Inventofls) Erich Kuehn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r- Page 1 of 3 a Column 2 line 24, after the last word in that line, "group l 7 insert the following and a phenyl group Column 3 line 44, formula (c) should read as follows:

c1 po(oc n 2 I C .I CO2CH2CHCH2-PO(OC4H9) c 1 CO2CH2CHCH2-PO(OC4H9) 2 Cl otocz sg) 2 Column 3, line 61, formula (e) should read as follows:

Column 5 line '56, after the word "60%" and before the word "weight", insert the word by Column 6 line 73, after the word "cellulose, insert the following words hydroxyethyl cellulose,

methyl hydroxyethy l cellulose,

(Continued on next page) i a 7 633; 7 UNITED STATES LXATENT OFFICE CERTIFICATE Oh CORRECTION 8,138 hated April 17, 1973 Invent 1-( 6 Erich Kuehn i It: is cert fied that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

:- a Page 2 of 3 Column 7, line 16 delete the word "sebasic" and insert in its place the word sebacic I Column 8,. line 6, the word "diphenylmethane-Z ,4'-diisocya" should read diphenylmethane-4,4

diisocyav Column 8, 'line 22, the word '0 .l/Y should read 0 .l

7 Column 8, line 32, the formula 'H O(C H O) (C H (C 1H O) H" should read Ho(C H o) (c H o) (c H o) Hv it Column 9 lines 63 t p 67, the figures under the heading "fieconds" should read as follows i Column 12, line 19 the number "4 .34" should read 43.4

(Continued on next page) I UNITED STATES PATENT OF FI CE CERTIFICATE CORRECTION Patent No. 1 3,728,138

Dated P 1973 Inventor(s )r Erich Kuehn It is certified that error a and that said Letters Patent are ppears in the above-identified patent hereby corrected as shovm below:

Page 3 of 3 r I I I Column 13, line 9 the word "fo-lowing" should read following Column 13, line 36 the formula should read as follows: V

1 ,t C H ?O (OC,4H9) 2 Cl CO2CH2'CHCH2-PO(OC4H9) 2 v (:1 CO2CH2('1HCH2PO(OC4H9)2 c1 PO(OC4H9) 2 Column 14, line 18, the word "K" should read X 2 Signed and sealed this 27th day of November 1973 (SEAL) Attest:

EDWARD M.FLETCHER,JR-. Attesting Officer RENE D. TEGTMEYER v Acting Commissioner of Patents 

